Editing Streator, Illinois (section)

===Topography and geology===
Streator lies within the Vermilion River/Illinois River Basin Assessment Area (VRAA) defined by the watershed of the Vermilion River, a major tributary to the [[Illinois River]] in [[Central Illinois]], an area of mostly flat [[prairie]]. The topography of the basin is a complex collection of [[buried valley]]s, lowlands and uplands carved by repeated episodes of continental glaciation.

Underneath the topsoil, the region's [[bedrock]] contains vast amounts of [[coal]].<ref name="VRAA01">{{Cite book |last=Office of Scientific Research and Analysis |url=http://www.dnr.state.il.us/publications/pdf/00000464.pdf |title=Vermilion River (Illinois River Basin) Area Assessment – Volume 1: Geology |date=2000-10-01 |publisher=Illinois Department of Natural Resources – State Geological Survey Division |page=105 |access-date=2008-10-26}}</ref>{{rp|14}} About 68% of Illinois has coal-bearing [[strata]] of the [[Pennsylvanian (geology)|Pennsylvanian]] geologic period. According to the [[Illinois State Geological Survey]], 211 billion tons of [[bituminous coal]] are estimated to lie under the surface, having a total heating value greater than the estimated oil deposits in the [[Arabian Peninsula]].<ref name="coal01">{{Cite web |last=Briedis |first=Cindy A. |date=2007-10-15 |title=Why Study Coal in Illinois? |url=http://www.isgs.illinois.edu/research/coal/illinois-coal.shtml |url-status=dead |archive-url=https://web.archive.org/web/20090731153444/http://www.isgs.illinois.edu/research/coal/illinois-coal.shtml |archive-date=July 31, 2009 |access-date=2008-12-04 |publisher=Illinois State Geological Survey}}</ref> However, this coal has a high [[sulfur]] content, which causes [[acid rain]].

Streator's coal mining history closely parallels Illinois', with a great push in coal production from 1866 until the 1920s, when many of the mines closed.  The low-sulfur coal of the [[Powder River Basin]] of [[Wyoming]] and the growing demands for oil caused a decline in demand for Streator's high-sulfur coal.

The [[St. Peter Sandstone]] is an [[Ordovician]] [[Formation (geology)|formation]] in the Chazyan stage of the [[Champlainian]] series. This layer runs east–west from Illinois to [[South Dakota]].  The stone consists of 99.44% [[quartz]] or silicon dioxide ([[silica|SiO<sub>2</sub>]]), which is used for the manufacture of glass.  Its purity is especially important to [[glassmaker]]s.  Streator, which lies within [[outcrop]] area of the St. Peter sandstone formation, has mined this mineral since the late 19th century for use in its glass manufacturing industries.<ref name="Kett01" />{{rp|228}}